English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We study the influence of X‐rays on the wind structure of selected O stars. For this purpose we use our non‐local thermodynamic equilibrium (NLTE) wind code with inclusion of additional artificial source of X‐rays, assumed to originate in the wind shocks.  We show that the influence of shock X‐ray emission on wind mass‐loss rate is relatively small. Wind terminal velocity may be slightly influenced by the presence of strong X‐ray sources, especially for stars cooler than   T  eff ≲ 35 000 K .  We discuss the origin of the   L  X / L ∼ 10 −7   relation. For stars with thick wind this relation can be explained assuming that the cooling time depends on wind density. Stars with optically thin winds exhibiting the ‘weak wind problem’ display enhanced X‐ray emission which may be connected with large shock cooling length. We propose that this effect can explain the ‘weak wind problem’.  Inclusion of X‐rays leads to a better agreement of the model ionization structure with observations. However, we do not find any significant influence of X‐rays on P  v  ionization fraction implying that the presence of X‐rays cannot explain the P  v  problem.  We study the implications of modified ionization equilibrium due to shock emission on the line transfer in the X‐ray region. We conclude that the X‐ray line profiles of helium‐like ions may be affected by the line absorption within the cool wind.

NLTE models of line‐driven stellar winds – III. Influence of X‐ray radiation on wind structure of O stars